Technical note: Optimizing the deliverability of binary collimation-based SRS treatment for multiple metastases with multiple prescriptions.

intra-arc binary collimation (iABC) is a novel treatment technique in which dynamic conformal arcs are periodically interrupted with binary collimation. It has demonstrated its utility through planning studies for the treatment of multiple metastases. However, the binary collimation approach is idealized in the planning system, while the treatment deliveries must adhere to the physical limitations of the mechanical systems involved [e.

Body contour adaptation for weight-loss and bolus for head and neck radiotherapy on Ethos version 2.0 and HyperSight: Synthetic CT versus direct calculation.

Purpose: In radiotherapy, body contour inaccuracies may compromise the delineation of adjacent structures and affect calculated dose. Here, we evaluate the un-editable body contours auto-generated by Ethos versions 1.0 (v1) and 2.

Cerebral Embolic Protection by Geographic Region: A Post Hoc Analysis of the PROTECTED TAVR Randomized Clinical Trial.

Importance: Transcatheter aortic valve replacement (TAVR) is an established treatment option for many patients with severe symptomatic aortic stenosis; however, debris dislodged during the procedure can cause embolic stroke. The Sentinel cerebral embolic protection (CEP) device is approved for capture and removal of embolic material during TAVR but its efficacy has been debated.

Objective: To explore regional differences in the association of CEP utilization with stroke outcomes in patients undergoing TAVR.

Serial and parallel organ-at-risk-specific noncoplanar arc optimization for small versus large target volumes in liver SBRT.

Noncoplanar arc optimization has been shown to reduce OAR doses in SRS/SRT and has the potential to reduce doses to OARs in SBRT. Extracranial targets have additional considerations, including large OARs and, in the case of the liver, volume constraints on the healthy liver. Considering pathlengths through OARs that encompass target volumes may lead to specific dose reductions as in the encompassing healthy liver tissue.

The feasibility of CT simulation-free adaptive radiation therapy.

Background: Novel on-board CBCT allows for improved image quality and Hounsfield unit accuracy. When coupled with online adaptive tools, this may have potential to allow for simulation and treatment to be completed in a single on-table session.

Purpose: To study the feasibility of a high-efficiency radiotherapy treatment workflow without the use of a separate session for simulation imaging.

Static couch non-coplanar arc selection optimization for lung SBRT treatment planning.

. Non-coplanar arc geometry optimizations that take advantage of beam's eye view (BEV) geometric overlap information have been proven to reduce dose to healthy organs-at-risk (OARs). Recently, a metric called mean arc distance (MAD) has been developed that quantifies the arc geometry sampling of 4space.

Skin/mucosa avoidance radiotherapy (SMART) versus conventional volumetric arc-based radiotherapy (VMAT) for the treatment of head and neck cancer: Dosimetric feasibility study.

Background: Intensity modulated radiotherapy (IMRT) for head and neck cancer has led to a reduction in radiotherapy doses to normal tissues, like the salivary glands, while maintaining high rates of local control. Oral mucosal and skin toxicity is still a major source of treatment-related morbidity, occurring in most patients.

Purpose: We conducted a dosimetric feasibility study with the goal of creating a methodology that could theoretically reduce the dose of radiation to skin and oral mucosa, while maintaining comparable avoidance of other organs at risk, and planning target volume (PTV) coverage.

Evaluation of plan quality and treatment efficiency in cranial stereotactic radiosurgery treatment plans with a variable source-to-axis distance.

Introduction: Radiotherapy deliveries with dynamic couch motions that shorten the source-to-axis distance (SAD) on a C-arm linac have the potential to increase treatment efficiency through the increase of the effective dose rate. In this investigation, we convert clinically deliverable volumetric modulated arc therapy (VMAT) and dynamic conformal arc (DCA) plans for cranial radiosurgery into virtual isocenter plans through implementation of couch trajectories that maintain the target at a shortened but variable SAD throughout treatment.

Materials And Methods: A randomly sampled population of patients treated with cranial radiosurgery from within the last three years were separated into groups with one, two, and three lesions.

Outcomes of the roll-in cohort of the Amulet IDE trial of left atrial appendage occlusion.

Background: Left atrial appendage (LAA) occlusion is an alternative therapy to oral anticoagulants to reduce stroke risk in patients with nonvalvular atrial fibrillation (NVAF). The Amulet IDE trial compared the Amplatzer™ Amulet™ occluder (Abbott) with the Watchman™ 2.5 device (Boston Scientific) for LAA occlusion in patients with NVAF.

Mean Arc Distance (MAD): a quantity to compare trajectory 4sampling in single target cranial stereotactic radiotherapy.

C-arm linac-based radiotherapy has seen a recent interest in 4methods of delivery using simultaneous rotations of couch and gantry to reduce doses to organs-at-risk (OARs) and increase dose compactness. While many methods use heuristics to generate trajectories that avoid OARs, combined with arbitrary trajectory restrictions to prevent oversampling, a quantity has not yet been developed to succinctly compare sampling of the 4space for candidate trajectories as a surrogate for dosimetric compactness.Evenly spaced sampling points were distributed across a 4sphere centred on isocentre.

Evaluation of parent and youth experiences in advisory groups as part of a mental healthcare clinical trial: protocol for a mixed-method study.

Introduction: Patient engagement in healthcare research is a necessity to ensure that research objectives align with priorities, outcomes and needs of the population under study, and to facilitate ease of implementation and adoption of findings. In clinical trials, there is an increasing focus on patient engagement during the planning and conduct of clinical trials due to the potential for ethical and methodological benefits. As patient engagement in clinical trials increases, there is a need to evaluate the approaches of these activities to contribute evidence on what is most appropriate and successful.

SCAI Guidelines for the Management of Patent Foramen Ovale.

Background: Patent foramen ovale (PFO) is a vestigial congenital cardiovascular structure present in around 25% of adults. In most cases, PFO is entirely benign and requires no treatment. However, it may cause serious complications under certain circumstances.

Intra-arc binary collimation with dynamic axes trajectory optimization for the SRS treatment of multiple metastases with multiple prescriptions.

Purpose: This work generates multi-metastases cranial stereotactic radiosurgery/radiotherapy (SRS/SRT) plans using a novel treatment planning technique in which dynamic couch, collimator, and gantry trajectories are used with periodic binary target collimation. The performance of this planning technique is evaluated against conventional volumetric arc therapy (VMAT) planning in terms of various dose and plan quality metrics.

Methods: A 3D cost space (referred to herein as the combined optimization of dynamic axes or CODA cube) was calculated based on an overlap between targets and organs-at-risk (OARs) and uncollimated areas between targets (island blocking) for all combinations of couch, gantry, and collimator angles.

Quantifying the Sensitivity of Target Dose on Intrafraction Displacement in Intracranial Stereotactic Radiosurgery.

Purpose: Mask-immobilized stereotactic radiosurgery (SRS) using a gating window is an emerging technology. However, the amount of intracranial tumor motion that can be tolerated during treatment while satisfying clinical dosimetric goals is unknown. The purpose of this study was to quantify the sensitivity of target dose to tumor motion.

Technical note: Personalized treatment gating thresholds in frameless stereotactic radiosurgery using predictions of dosimetric fidelity and treatment interruption.

Purpose: Gamma Knife Icon (GKI) enables a user-defined gating threshold for intrafraction motion during stereotactic radiosurgery (SRS). An optimal threshold would ensure dosimetric fidelity of the planned distribution and minimize treatment time extension by gating. A prediction of motion characteristics for a patient based on a retrospective database of motion traces could be beneficial to evaluating the choice of gating threshold.

SBRT of ventricular tachycardia using 4pi optimized trajectories.

Purpose: To investigate the possible advantages of using 4pi-optimized arc trajectories in stereotactic body radiation therapy of ventricular tachycardia (VT-SBRT) to minimize exposure of healthy tissues.

Methods And Materials: Thorax computed tomography (CT) data for 15 patients were used for contouring organs at risk (OARs) and defining realistic planning target volumes (PTVs). A conventional trajectory plan, defined as two full coplanar arcs was compared to an optimized-trajectory plan provided by a 4pi algorithm that penalizes geometric overlap of PTV and OARs in the beam's-eye-view.

Amplatzer Amulet Left Atrial Appendage Occluder Versus Watchman Device for Stroke Prophylaxis (Amulet IDE): A Randomized, Controlled Trial.

Background: Percutaneous closure of the left atrial appendage (LAA) is an alternative to chronic oral anticoagulation to reduce stroke risk in patients with nonvalvular atrial fibrillation. The Amulet IDE trial (Amplatzer Amulet Left Atrial Appendage Occluder IDE Trial) was designed to evaluate the safety and effectiveness of the dual-seal mechanism of the Amulet LAA occluder compared with the Watchman device.

Methods: Patients with nonvalvular atrial fibrillation at increased risk of stroke were randomly assigned (1:1) to undergo percutaneous implantation of a LAA occluder with the Amulet occluder or Watchman device.

PEMIP: Post-fire erosion model inter-comparison project.

Land managers often need to predict watershed-scale erosion rates after disturbance or other land cover changes. This study compared commonly used hillslope erosion models to simulate post-fire sediment yields (SY) at both hillslope and watershed scales within the High Park Fire, Colorado, U.S.

Toward the combined optimization of dynamic axes (CODA) for stereotactic radiotherapy and radiosurgery using fixed couch trajectories.

Purpose: To develop a novel system for patient-specific combined optimization of couch, collimator, and gantry angles for use in volumetric modulated arc therapy (VMAT) treatment planning. The system was designed to produce highly compact dose distributions by extensively sampling the 4π space. Automated fixed couch trajectory planning was used to reduce normal tissue doses by avoiding beams-eye-view (BEV) overlap with organs-at-risk (OARs) and improve monitor unit (MU) efficiency through collimator angle optimization.

Real-Time Infrared Motion Tracking Analysis for Patients Treated With Gated Frameless Image Guided Stereotactic Radiosurgery.

Purpose: The transition from frame-based brain stereotactic radiosurgery (SRS) to frameless delivery is supported by real-time intrafraction monitoring to ensure accurate delivery. The purpose of this study is to characterize these real-time motion traces in a large cohort of patients treated with frameless gated brain SRS and to develop patient-specific predictions of tolerance violations.

Methods And Materials: SRS patients treated on the Gamma Knife Icon were immobilized using a device-specific thermoplastic head mask.

Rationale and design for AMPLATZER Amulet Left Atrial Appendage Occluder IDE randomized controlled trial (Amulet IDE Trial).

The Amulet IDE Trial is an ongoing, prospective, randomized, multi-national trial, designed to evaluate the safety and effectiveness of the AMPLATZER Amulet Left Atrial Appendage Occluder for stroke prevention in comparison to the WATCHMAN Left Atrial Appendage Closure Device in patients with non-valvular atrial fibrillation. METHODS: Non-valvular atrial fibrillation patients at high risk of stroke (CHADS score ≥2 or a CHADS-VASc score of ≥3) who are suitable candidates for left atrial appendage occlusion (LAAO) will be fully informed and requested to participate in the trial. A total of 1878 patients at up to 150 sites worldwide will be randomized in a 1:1 ratio between the AMPLATZER Amulet device (investigational) and the Boston Scientific WATCHMAN device (control).

University physicists and the origins of the National Physical Laboratory, 1830-1900.

Traditionally, historians have taken it for granted that Britain's National Physical Laboratory (NPL) was created as the result of demands from a "professional" body of university-based physicists for a state-funded scientific institution. Yet paying detailed attention to the history of the NPL's originating institution, Kew Observatory, shows that the story is not so clear-cut. Starting in the 1850s, Kew Observatory was partly a center for testing meteorological instruments and other scientific equipment in return for fees.

Intra-arc binary collimation algorithm for the optimization of stereotactic radiotherapy treatment of multiple metastases with multiple prescriptions.

Purpose: To design and implement a novel treatment planning algorithm based on a modification of dynamic conformal arc (DCA) therapy for the treatment of multiple cranial metastases with variable prescription doses.

Methods: A workflow was developed in which separate dose matrices were calculated for each target at each control point (i.e.